<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
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    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        function Person(){
            this.song = function(){
                console.log("唱歌");
            }
        }

        let p = new Person();

        Person.song = function(){
            console.log('唱歌了');
        }

        Person.song()

        // Object.keys();

        
    </script>
</body>
</html>